Bump @rollup/plugin-commonjs from 26.0.1 to 28.0.0

Bumps [@rollup/plugin-commonjs](https://github.com/rollup/plugins/tree/HEAD/packages/commonjs) from 26.0.1 to 28.0.0.
- [Changelog](https://github.com/rollup/plugins/blob/master/packages/commonjs/CHANGELOG.md)
- [Commits](https://github.com/rollup/plugins/commits/commonjs-v28.0.0/packages/commonjs)

---
updated-dependencies:
- dependency-name: "@rollup/plugin-commonjs"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -55,7 +55,7 @@
     "@11ty/eleventy": "^2.0.0",
     "@11ty/eleventy-navigation": "^0.3.2",
     "@11ty/eleventy-plugin-rss": "^1.0.0",
-    "@rollup/plugin-commonjs": "^26.0.0",
+    "@rollup/plugin-commonjs": "^28.0.0",
     "@rollup/plugin-node-resolve": "^15.0.0",
     "@x-govuk/govuk-prototype-components": "^3.0.0",
     "deepmerge": "^4.2.2",